Appearance-based object recognition using shape-from-shading

This paper investigates the use of shape-from-shading for object recognition. The local surface orientation information recovered using shape-from-shading is shown to provide useful input to an appearance-based object recognition scheme. We consider two representations which may be recovered from shading information-the needle-map, and the local curvature shape-index-and their relative performance for object recognition. Specifically, we use a histogram-comparison technique, and focus upon the relative stability of the representations to small changes of viewpoint. We demonstrate that the needle-map representation allows the view-sphere to be spanned using a significantly smaller number of characteristic views than using either the raw images or the shape index